An automatic testing machine (ATM) operates in a production environment to rapidly and accurately test the operation and performance of various types of devices under test (DUT), including RF communication devices. The DUTs could be a finished product or a component of a larger system.
The ATM is programmed to perform various tests on the DUT automatically. For example, RF signals are transmitted to a finished cellular telephone DUT to determine if the telephone activates. Other tests could include environmental tests, such as temperature or vibration tests.
Depending upon the nature and number of the tests being performed, the testing may last from a couple of milliseconds to several minutes. The information from the testing is compared with expected test results. If there is some defect so that the DUT falls below specifications, the ATM will designate the DUT as failed, either by marking the DUT, placing the DUT in a failure area, or indicating the failure to an operator.
The ATM is then loaded with the next DUT, either manually or automatically, and the testing procedure is repeated for this DUT. The information from the testing can be used to evaluate the fabrication process for possible changes, as well as to perform failure analysis on individual failed devices.
Typically, each ATM is designed to perform a specific class of tests on the DUT, and are not able to perform other classes of tests. For example, a vibration ATM may not be able to perform electrical signal tests. However, different types of DUTs may require the same tests to be performed. For example, all types of microcomputer chips are tested for electronic performance characteristics, but different chips will have different locations for power, inputs and outputs. ATMs are made flexible by the use of test fixtures. The test fixture provides an interface between the device under test DUT and the ATM. Thus, a single ATM can perform tests on different types of devices when connected via different fixtures.
However, fixtures tend to be large and bulky. Moreover, they have numerous connections to the ATM for the required resources to allow testing, e.g. power, electronic signals, RF signals, and pneumatic air pressure. Thus changing fixtures is time consuming, as each individual connection to the ATM must be separated, the current fixture removed, and then the new fixture installed. During the replacement process, the production line is shut down, which results in lost production time. If the fixture needs to be repaired, then this process must be undertaken, and the lost production time is unavoidable. However, if the fixture is to be changed merely to accommodate a different DUT, then the lost production time can be mitigated by using an adapter. An adapter is a DUT holder that is coupled to the fixture. The adapter is customized to hold a specific type of DUT. If a different DUT needs to be tested then the adapter in the fixture is swapped for the proper adapter.
A particular class of fixtures are RF fixtures. RF fixtures are used in the testing of DUTs that operate with radio waves, e.g. cellular telephones, pagers, CB radios, etc. The RF fixture is sealed such that external electromagnetic fields or radio waves do not affect the testing of the DUT. Thus, the RF testing being performed on the DUT will be performed accurately, as the DUT will receive only the test RF signals and not any external RF signals which may skew the operation of the DUT. In order to load the DUTs into the fixture, a drawer mechanism is used. A problem arises when adapters are used with RF fixtures having a drawer mechanism.
As shown in FIG. 3, adapter 31 is connected to drawer 34 of fixture 33. RF door 32 is rigidly connected to drawer 34. The arrows 35 indicate the path taken by adapter 31 during its removal from fixture 33. To avoid door 32 and the top of fixture 33, adapter 31 must be lifted vertically to clear door 32, then horizontally to clear the top of fixture 33. Adapters generally are heavy and have fragile connections that are easily damaged. Thus, if adapter 31 collides with either door 32 or the top of fixture 33, then it is likely that adapter 31 will be damaged in some manner.
The damage to adapter 31 may occur without notice by the technician. Thus, when the damaged adapter is subsequently used, then incorrect information about the DUT may be collected. The incorrect information could lead to improperly passing a defective DUT or failing a passing DUT. The incorrect information may also result in incorrect or unnecessary changes being made to the production process. Moreover, the damaged adapter may cause damage to the DUT, the fixture, or the ATM.
Furthermore, since adapter 31 is customized to a particular DUT, multiple copies of the adapter are not usually maintained. Thus, if the adapter is damaged, a backup is not likely to be available. Thus, the production line of the DUT may be halted until the damaged adapter is repaired.
Therefore, there is a need in the art for a system and method that allows for the rapid and reliable replacement of fixture adapters in a production environment.